204 PRACTICAL ORGANIC CHEMISTRY
Cinnamic Acid (Phenylacrylic Acid),
Bertaq-nt-ni, Animlcn, 1856, 100, 126; Perkin, Trans. Chcm.
Soi;, 1868, 21, 53 ; Fittig, Ber., i8Si,14, 1826.
20 grms. benzaldehyde.
10 „ sodium acetate (fused).
30 . „ acetic anhydride.
The mixture of benzaldehyde, sodium acetate, and acetic an-
hydride is heated to 180° in a small round flask with upright
condenser in an oil-bath for about eight hours. The mass is
poured out whilst hot into a large round flask (i. litre), sodium
carbonate added until alkaline, and any unchanged benzaldehyde
distilled off with steam. After filtering from tindissolved resin-
ous by-products, hydrochloric acid is added, which precipitates
the free cinnamic acid in white crystalline flakes. It may
be purified by recrystallisation from hot water. Yield, 15 — 20
Properties.— Colourless prisms ; m. p. 133° ; b. p. 300 — 304°-
See Appendix, p. 304
Hydrocinnamic Acid (Phenylpropionic Acid),
Erlenmeyer, Alexejeff, Annalcn, 1862, 121, 375, and 1866,
10 grms. cinnamic acid.
100 „ water.
170 „ sodium amalgam (2-J per cent).
The sodium amalgam is prepared by warming 200 grams of
mercury in a porcelain basin for a few minutes. The mercury